1. Field of the Invention
The present invention relates to a tandem pulse arc welding control apparatus that controls the length of an arc in tandem pulse arc welding in which a pulse cycle for a first welding wire and a pulse cycle for a second welding wire insulated from the first welding wire are synchronized with each other, and in tandem pulse arc welding in which the pulse cycle for the first welding wire and the pulse cycle for the second welding wire are made to have a phase difference, which is set in advance, therebetween, and relates to a system therefor.
2. Description of the Related Art
Hitherto, multi-electrode arc welding apparatuses having two welding wires for one welding torch have been proposed because the multi-electrode arc welding apparatuses have advantages in that the welding speed is high, the amount of spatter that occurs is small, the welding bead has a good appearance, and so forth (for example, see Japanese Unexamined Patent Application Publication No. 2002-263838).
The invention described in Japanese Unexamined Patent Application Publication No. 2002-263838 given above is a method for controlling a multi-electrode pulse arc welding apparatus in which a pulse cycle for a first welding wire is changed, and in which a peak current value for a second welding wire is changed. Accordingly, in the invention, the average value of a welding voltage at the second welding wire is varied, thereby reducing variation in the length of an arc for the second welding wire and so forth. Thus, a high welding quality can be realized.
However, in the invention described in Japanese Unexamined Patent Application Publication No. 2002-263838 given above, there may be a case in which an appropriate welding current cannot be obtained because the range of variation in the average value of the welding voltage at the second welding wire is narrow. As a result, the invention has a problem that a high welding quality cannot be realized.